Similarly, microbiota-responsive IFN-γ+Foxp3+ iTreg cells failed to induce colitis upon transfer to RAG−/− hosts, instead retaining suppressive function, protecting against disease transferred by Foxp3− T cells 25. A protective role for IFN-γ and a contribution of this cytokine to suppressive function in vivo has been suggested in a skin graft tolerance model 26. The gene discussed is FOXP3; the disease is colitis.